NSF/ANSI/CAN 61 Pressure Instruments

NSF/ANSI/CAN 61: Scope and Purpose

NSF/ANSI/CAN 61 is a health-effects standard for components, materials, and products that contact drinking water. Its purpose is to evaluate whether wetted materials can contribute contaminants to potable water at concentrations above the standard’s applicable acceptance criteria.

For pressure instruments, the relevant question is not simply whether a gauge, transmitter, switch, or accessory is installed on a water line. It is whether the specific parts exposed to drinking water—including process connections, sensing elements, diaphragms, seals, fill fluids where applicable, and other wetted components—are covered by the certified product configuration.

The standard evaluates contaminant migration under defined exposure conditions. In practical terms, samples or representative product configurations are exposed to test water, and the resulting water is analyzed for substances that may migrate from the product. Depending on the product and material category, evaluation can address metals and organic contaminants. The result is a health-effects assessment of the product’s contribution to drinking-water quality, rather than a general statement about mechanical performance.

NSF/ANSI/CAN 61 should not be treated as a blanket approval for every product sold by a manufacturer. Certification is normally specific to the listed product, construction, material set, and intended use. A change in wetted material, elastomer, coating, connection design, process size, or manufacturing arrangement can affect whether a configuration remains within the certification scope.

It is also important to distinguish NSF/ANSI/CAN 61 from NSF/ANSI/CAN 372. NSF/ANSI/CAN 61 addresses health effects associated with drinking-water contact materials, including contaminant extraction or leaching. NSF/ANSI/CAN 372 addresses lead-content requirements for drinking-water system components. In many current certification programs and product categories, the two requirements may be addressed together, but purchasers should not assume that one marking automatically confirms every requirement for every configuration.

When specifying NSF/ANSI/CAN 61 pressure instruments, confirm the current third-party certification listing, manufacturer documentation, and the exact product scope. The applicable documentation should identify the certified product family or model, relevant wetted materials, and any limitations on size, use, or configuration. Certification programs may also include continuing oversight of the manufacturing process, documentation, or facilities, subject to the certifier’s current program requirements.

How NSF/ANSI/CAN 61 Supports Drinking-Water Protection

Drinking-water systems contain many components that can contact water for extended periods: pipe, valves, fittings, tanks, pumps, meters, sensors, pressure instruments, seals, and treatment equipment. Even when a component performs its mechanical function correctly, its wetted materials may introduce substances into the water through leaching or extraction.

Materials of concern can include metals and organic compounds. The risk depends on the material composition, water chemistry, temperature, contact time, surface area relative to water volume, and the particular use of the product. A material that is suitable for industrial water, wastewater, hydraulic oil, or compressed air is not automatically appropriate for potable-water contact.

NSF/ANSI/CAN 61 provides a common method for evaluating this issue. Rather than relying only on a material name—such as stainless steel, brass, polymer, elastomer, or epoxy—the standard considers the product or material in a defined drinking-water-contact context. This approach is useful because apparently similar products can contain different alloys, additives, coatings, curing agents, elastomers, lubricants, or process-contact assemblies.

The standard itself is a voluntary consensus standard. However, its use can become effectively required for a particular application when it is referenced by a state or local rule, water utility requirement, plumbing code, project specification, engineer’s procurement document, or authority having jurisdiction. Requirements therefore vary by location and project type.

A manufacturer’s declaration that a material is suitable for water service is not equivalent to third-party certification. Certification indicates that the listed configuration has been evaluated within a recognized certification program. That distinction is particularly important when a project specification explicitly calls for NSF/ANSI/CAN 61 certification or when records must be provided during submittal review.

NSF/ANSI/CAN 61 should not be described as a universal federal mandate directly enforced by the U.S. Environmental Protection Agency for every drinking-water component. Regulatory adoption and enforcement mechanisms differ among jurisdictions. Buyers, designers, and installers should identify the actual requirement that applies to the project rather than relying on a general assumption about federal, state, or local enforcement.

Regulatory Value of a Recognized Health-Effects Standard

A recognized health-effects standard gives system owners, regulators, consulting engineers, manufacturers, and contractors a common basis for evaluating drinking-water-contact products. Instead of requiring each project team to develop its own extraction tests and acceptance limits, a specification can reference an established standard and request evidence of certification.

This common framework can simplify technical communication. A submittal may identify the product model, certification body, listing or certificate reference, and certified configuration. The project reviewer can then compare that evidence with the required service conditions and procurement specification.

The value of certification is strongest when it is connected to a clearly defined application. For example, a potable-water pressure gauge may need to satisfy a health-effects requirement while also meeting the system’s pressure range, connection type, temperature exposure, installation orientation, environmental protection needs, and readability requirements. Certification addresses one important part of suitability; it does not replace the rest of the engineering review.

Adoption and acceptance vary. One utility may require third-party certification for all components in contact with treated drinking water, while another may impose requirements only on selected component categories. A municipal project may have different documentation expectations from an industrial facility with a private water system. Contract documents may also specify a particular certifier, listing format, or submittal procedure.

For this reason, project teams should verify requirements with the relevant authority having jurisdiction, utility, owner, and contract documents. Public-health protection and confidence in drinking-water infrastructure are intended outcomes of using recognized health-effects standards, but the legal effect of a certification depends on how the standard is adopted for the specific project.

What Certified Components Mean for Water-System Users

For a water-system user, third-party certification means that a listed product configuration has been evaluated against the applicable health-effects requirements of the certification program. It can provide documented support when a purchaser must show that a component intended for drinking-water contact meets a referenced standard.

This documentation can be valuable during design review, procurement, installation, inspection, and turnover. It may help demonstrate conformance when a utility, specification, or authority having jurisdiction requires certified components. It also gives the buyer a defined basis for comparing products that may appear mechanically similar but differ in wetted materials or certification scope.

However, certification does not guarantee that a pressure instrument is suitable for every water-system duty. Users should still review the following factors:

Certified configuration: Verify that the exact model, wetted construction, connection, and accessory arrangement are included in the current listing.
Pressure capability: Select an instrument with a pressure range and overpressure capability appropriate for normal operation, startup, pump cycling, and expected transients.
Temperature conditions: Confirm both process-fluid and ambient-temperature suitability.
Media compatibility: Potable water is not chemically identical in every system. Treatment chemicals, disinfectants, residuals, cleaning agents, and dissolved solids may affect material selection.
Installation conditions: Consider vibration, pulsation, outdoor exposure, enclosure needs, accessibility, and the risk of freezing.
Measurement function: A local gauge, pressure transducer, and pressure switch perform different roles and should be selected according to whether the system needs indication, continuous signal output, alarm, interlock, or control.
Maintenance and calibration: Certification does not remove the need for inspection, calibration verification where required, isolation provisions, or safe replacement procedures.

A certified wetted assembly also does not establish the durability, accuracy, service life, corrosion resistance, or maintenance requirements of the complete instrument. Those characteristics must be evaluated using the manufacturer’s technical documentation and the actual operating conditions.

Ashcroft Pressure Instruments Certified to NSF/ANSI/CAN 61

Ashcroft announced that select pressure instruments and accessories intended for potable-water applications received NSF/ANSI/CAN 61 certification. The announcement covers selected pressure gauges, pressure transducers, pressure switches, diaphragm seals, and isolation rings.

For engineers and buyers, this announcement is useful as an indication that potable-water-specific product options may be available within those categories. It should not be interpreted to mean that every Ashcroft product is certified, or that all versions of a listed model share the same certification status.

Pressure instruments are often specified with numerous options: pressure range, dial size, process connection, wetted alloy, diaphragm material, seal arrangement, filling, electrical output, enclosure, and mounting configuration. A certification listing may apply only to particular combinations of these features. The current manufacturer documentation and the certification body’s listing should therefore be checked before a product is specified, purchased, or installed.

This verification is especially important where a device is supplied as part of an assembled measurement system. A certified gauge or transmitter may be paired with a diaphragm seal, isolation ring, adapter, valve, or other process connection. If those added components contact potable water, the installed assembly should be reviewed as a whole rather than assuming that certification of one item extends automatically to every attached component.

The potable-water certification question should also be separated from other application questions. A product may be appropriate from a drinking-water health-effects perspective but require additional assessment for pressure cycling, surge events, vibration, enclosure rating, electrical classification, wastewater solids, chemical exposure, or service accessibility.

Certified Instrument Categories for Water and Wastewater Service

The reported Ashcroft NSF/ANSI/CAN 61-certified categories include pressure gauges, pressure transducers, pressure switches, diaphragm seals, and isolation rings for potable-water applications. These components serve different measurement and protection functions in water-system installations.

A pressure gauge provides local visual indication. It is commonly used at pumps, filters, treatment skids, storage systems, distribution equipment, and other points where an operator needs to observe line pressure directly. Local indication can help identify operating changes such as a pressure drop across a filter, a pump discharge condition, or an abnormal system pressure.

A pressure transducer converts pressure into an electrical signal for a controller, remote display, supervisory system, or data-acquisition system. In a water facility, transducers may support continuous monitoring, pump control, tank level calculations based on hydrostatic pressure, alarm functions, or operational trending. The electrical output type and control-system compatibility must be selected separately from the potable-water certification requirement.

A pressure switch changes electrical state at a selected pressure condition. It can be used for alarms, pump sequencing, protective shutdown, or simple control functions. Setpoint range, switching behavior, electrical rating, and expected pressure cycling should be evaluated for the specific installation.

A diaphragm seal separates the pressure-sensing instrument from the process fluid through a flexible diaphragm and a pressure-transfer arrangement. An isolation ring can serve a related purpose in certain process connections. These accessories may be considered where direct connection of an instrument is undesirable because of process conditions or installation needs. Their actual suitability depends on the media, connection geometry, temperature, pressure behavior, cleaning requirements, and maintenance practices.

Ashcroft identified the following gauge models in its reported certification announcement:

1008-S
1009-SW Duralife
1279-S Duragauge

These model references should be treated as starting points for documentation review, not as confirmation that every version is certified. Before selecting one of these gauges, confirm the current certified configuration, including the wetted construction and applicable process connection. The same caution applies to reported certified transducer, switch, diaphragm-seal, and isolation-ring families.

Water and wastewater service should also be evaluated separately. Potable-water certification addresses drinking-water-contact health effects. Wastewater applications can present different selection issues, including suspended solids, deposits, biological fouling, treatment chemicals, corrosive constituents, pulsation, and difficult access for maintenance. A device selected for treated drinking water may not be appropriate for raw wastewater, sludge, chemical-feed service, or another aggressive process without additional engineering review.

In all cases, the selection process should combine certification verification with normal instrument engineering practice: define the medium, pressure conditions, required measurement function, wetted-material compatibility, installation arrangement, environmental conditions, and applicable local or project requirements.